The word "altcoin "is an abbreviation for" Bitcoin alternatives", and they are called all cryptocurrencies except bitcoin. Altcoins are called an alternative to bitcoin, as most altcoins hope to either replace bitcoin or improve at least one of the parameters of bitcoin.
There are hundreds of altcoins, for example, the site Coinmarketcap lists more than 1000 altcoins . Every day there are more and more altcoins. Most altcoins are not much more than just clones of bitcoin, while changing only 1-2 minor characteristics, such as the speed of the transaction of coins in the network, the method of distribution of coins, or mining algorithm. Most of these coins do not live for a long time. The only exception is Litecoin (Litecoin), due to the fact that it was created as one of the first altcoins. Compared to Bitcoin, litecoin has a different mining algorithm and a much larger number of coins. For this reason the litecoin established themselves as the silver to gold